The invention relates to a method and a device for adjusting the liquid content of a solid withdrawn from a self-discharging centrifugal drum of a separator, and to a device for implementing this method.
In the case of several products, it is desirable that the solid withdrawn from self-discharging centrifugal drums has a content of dry substance which is as large as possible. It is therefore preferred to prevent liquid from being ejected from the drum along with the solid. In order to achieve this, a so-called xe2x80x9cpartial dischargexe2x80x9d is applied in which the centrifugal drum is opened only for such a short time that the majority of solids can escape.
In the case of other products, it is desirable to eject the solid with a liquid content which determines the endeavored consistency.
This cannot be achieved by means of the known separators and their method of operation.
It is an object of the invention to design a method and a device of the initially mentioned type such that, prior to the withdrawal of the solid from the centrifugal drum, the liquid content can be adjusted which determines the consistency.
According to the invention, when the separator is brought to a halt after separation, the liquid remaining in the interior of the centrifugal drum is aspirated until a quantity remains which corresponds to the required consistency of the solid. Subsequently the centrifugal drum is emptied at a suitable rotational speed, and then the solid is withdrawn from the centrifugal drum.
For the aspiration of a portion of the liquid from the interior of the centrifugal drum, the feeding tube feeds the solid/liquid mixture to the centrifugal drum and which can be adjusted with respect to its height and, in the lower end position, extends into the proximity of the drum bottom.
When the centrifugal drum is stopped, an inward and downward sloped drum bottom guides the residual fluid toward the interior and collects in the area of the lower end of the centrally arranged feeding tube.
Because of the axial displaceability of the feeding tube, the free end can be moved to the lowest point of the drum bottom, so that the liquid can also be almost completely aspirated through the feeding tube when the inflow is shut off. Furthermore, by way of the adjusted distance of the lower opening of the feeding tube from the drum bottom, a remaining fluid quantity can be adjusted and the consistency of the withdrawn solid can be influenced.
By using the feeding tube as a suction tube when the inflow of the solid/liquid mixture is switched off, a simple construction is obtained for carrying out the suction operation in order to withdraw a desired liquid quantity from the interior of the centrifugal drum.
The temporary use of the feeding tube as a suction tube is possible in the case of stationary as well as co-rotating feeding tubes.
Other objects, advantages and novel features of the present invention will become apparent from the following detail description of the invention when considered in conjunction with the accompanying drawings.